Purpose The purpose of this study is to understand the magnitude of the impact advergames have on children’s preferences and choices for unhealthy products and brands, in terms of time of exposure (immediate vs delayed) and number of exposures (single vs repeated exposure). Past literature has focused essentially on the immediate effects of single exposures to advergames. Few studies explored the delayed or repetition effects and found wear-out effects of multiple exposure and also no delayed effects of single exposure. Therefore, this study will reduce the existent gap in the literature by studying simultaneously both effects. Design/methodology/approach A sample of 104 children aged 6-9 years old was used, divided into three groups (no exposure/single exposure/repeated exposure) in an experimental between-subjects design setting. Findings The results confirm the existence of all the expected effects: exposure to advergames has immediate and longer effects on a child’s preferences and choices of the brand depicted in the advergame and in that product category. Repeated exposure to the advergame enhances all the effects on the brand, but not on the product category. Originality/value Although earlier literature has already analyzed time and repetition effects on traditional media, or sought to analyze effects of advergames but with an adult sample, this article highlights the extent of these effects with children, and based on these results, reflects on the ethicality of using advergames with children on products high in fat, salt and/or sugar.